Black time is, depending on of course the urgency of the appointment 1-4 hours.

Other factors such as family, work, and random meetings between acquaintances can add an extra half an hour.
People that are usually on "black time" are over popular people for whatever reason, or a person with no backbone.

Tanya- When is your friend coming by to hangout?
Sean- He didn't give me a time. He said he would be here soon though. Then again you know how he is always on "black time."

For those of you who do now understand the meaning of the term 'Black Time'. Black Time is the time zone, in which most black people use when attending a party or social event, some of you may describe this as being 'fashionably late' but on an extreme level. The culprit will usually arrive 1-5 hours late, depending on the length of the social event!

Person 1 - Hey the party started 3 hours ago why are you so late?
Person 2 - Oh! I was running on (black time)
Person 1 - Ohhhhh!